Data reception and transmission method and apparatus for power saving in communication system using multiple carriers

ABSTRACT

The present invention relates to a multi-carrier resource utilization method and apparatus for power saving in a communication system using a multi-carrier, in which the activation of a secondary carrier for transmitting and receiving data traffic between a terminal and a base station is determined according to the QoS (Quality of Service) requirements such as a data traffic status between the terminal and the base station, a maximum sustained traffic rate, a maximum traffic burst size, or the like, and an indication message (Indication) indicating this is transferred to the terminal through a primary carrier to transmit and receive data traffic through the activated secondary carrier.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of U.S. patentapplication Ser. No. 13/054,478, filed on Jan. 14, 2011, currentlypending, which is the National Stage filing under 35 U.S.C. 371 ofInternational Application No PCT/KR2009/003936, filed on Jul. 16, 2009,which claims the benefit of earlier filing date and right of priority toKorean Application No. 10-2009-0064662, filed on Jul. 15, 2009, and alsoclaims the benefit of U.S. Provisional Application Ser. Nos. 61/090,239,filed on Aug. 20, 2008, and 61/081,713, filed on Jul. 17, 2008, thecontents of which are all incorporated by reference herein in theirentirety.

TECHNICAL FIELD

The present invention relates to a resource utilization apparatus andmethod for power saving in a multi-carrier communication system, andmore particularly, to an apparatus and method for preventing theresource consumption and unnecessary power consumption of a terminal byactivating or deactivating multi-carriers allocated to the terminalbased on the status of data traffic.

BACKGROUND ART

With the development of the communication technology, services providedby a mobile communication system are being gradually developed intopacket data transmission and reception services, multimedia broadcastingservices, and the like, as well as voice communication services.

In the third generation services, such as WCDMA currently beingserviced, high capacity data as well as voice can be transmitted andreceived at a high transmission rate, and furthermore, thestandardization work is actively carried out, such as long-termevolution network (LTE), IEEE 802.16m, and the like, in order to make anevolved network having a wider bandwidth, considering a rapid increaseof data traffic in the future.

In particular, IEEE 802.16m, for which its standardization work isactively carried out, has set a goal to develop a standard specificationsatisfying the requirement of an IMT-Advanced system while maintainingcompatibility with existing 802.16-based terminals and base stationequipment. In the IMT-Advanced system, above all, more than 40 MHz ofbroadband communication service support is required, and in IEEE802.16m, broadband communication support is also essential to satisfythe requirement of the IMT-Advanced system. However, it is in factdifficult to define a standard for all bandwidths, and as a result, acommunication system using a multi-carrier approach that supportsbroadband using a plurality of carriers is under discussion. In themulti-carrier system, discussed under IEEE 802.16m, it is possible totransmit and/or receive data between a terminal and a base station byaccessing to each other through at least two and more frequencyassignments (FAs) at the same time, and therefore, it has an advantagethat high-capacity, high-speed data transmission and reception ispossible compared to the existing single-carrier approaches. Also, ithas a feature that communication is possible using a broader bandwidthfrom the standpoint of a mobile station (MS) depending on circumstances,and more users can be accommodated from the standpoint of a base station(BS).

However, in the multi-carrier system, when the terminal allocates CQIchannels, respectively, for all carriers allocated by the base station,CQI channels are allocated even to the channels for which data trafficis not actually generated, thereby creating a problem of generatingresource consumption. Furthermore, in the terminal, all the relevant RFmodules are turned on for all carriers allocated by the base stationregardless of whether or not data traffic is actually generated, therebycreating a problem of having serious power consumption.

DISCLOSURE OF THE INVENTION

As described above, an aspect of the present disclosure is to provide anapparatus and method for preventing resource consumption and unnecessarypower consumption of a terminal by suitably activating or deactivatingmulti-carriers allocated to the terminal according to its capabilitysuch as a data traffic status, a maximum sustained traffic rate, or amaximum traffic burst size, in order to solve a problem of generatingresource consumption and unnecessary power consumption of a terminal ina conventional communication system having a multi-carrier method inwhich CQI channels are allocated or terminal RFs are unnecessarilyturned on though data traffic is not actually generated for all carriersallocated to the terminal.

In order to accomplish the foregoing object, according to a method oftransmitting and receiving data using a multi-carrier in accordance withan embodiment of the present invention,

in a method of allowing a base station and a terminal to transmit andreceive data using at least one or more carriers in a communicationsystem using a multi-carrier including a primary carrier fortransmitting and receiving PHY/MAC control information and data forcommunicating between the base station and the terminal,

the method may include determining the activation of a secondary carrierfor transmitting and receiving data traffic between the base station andthe terminal; transferring an indication message (Indication) indicatingthe activation of the secondary carrier to the terminal through theprimary carrier; and transmitting the data traffic to the terminalthrough the activated secondary carrier.

Preferably, the method of transmitting and receiving data using amulti-carrier, in said transferring a secondary carrier activationindication message, may further include transferring an activationindication message of the secondary carrier to the terminal, and thenreceiving an activation confirmation message of the secondary carrierfrom the terminal.

Preferably, the method of transmitting and receiving data using amulti-carrier may further include transferring an indication messageindicating the deactivation of the secondary carrier to the terminalthrough the primary carrier or secondary carrier, and receiving adeactivation confirmation message of the secondary carrier from theterminal.

Preferably, it is characterized in that the indication message includescarrier index information indicating an index of the secondary carrier;and operation information indicating the activation or deactivationoperation of the secondary carrier indicated by the carrier index, andpreferably, it is characterized by further including offset informationindicating a timing for implementing the activation or deactivationoperation.

Preferably, it is characterized in that the indication message has anyone form of an extended subheader, a signaling header, a piggy backmessage, a map information message, and a MAC (medium access control)management message.

Preferably, according to the method of transmitting and receiving datausing a multi-carrier, in said determining the activation of thesecondary carrier, it is characterized in that the activation of thesecondary carrier is determined according to a data traffic statusbetween the terminal and base station, a maximum sustained traffic rate,or a maximum traffic burst size.

In order to accomplish the foregoing object, according to a method oftransmitting and receiving data using a multi-carrier in accordance withan embodiment of the present invention,

in a method of transmitting and receiving data using a multi-carrierincluding a primary carrier for transmitting and receiving PHY/MACcontrol information and data for communicating with a base station andat least one or more secondary carriers using the primary carrier andother RFs (radio frequencies) in a terminal supporting themulti-carrier, the method may include receiving an indication message(Indication) indicating the activation of the secondary carrier from thebase station through the primary carrier; turning on the RF of thesecondary carrier and activating the secondary carrier; and receivingdata from the base station through the activated secondary carrier.

Preferably, the method of transmitting and receiving data using amulti-carrier according to an embodiment of the present invention mayfurther include transferring an activation confirmation message of thesecondary carrier to the base station through the primary carrier.

Preferably, the method of transmitting and receiving data using amulti-carrier according to an embodiment of the present invention mayfurther include receiving an indication message indicating thedeactivation of the secondary carrier from the base station through theprimary carrier or secondary carrier; and turning off the RF of thesecondary carrier and deactivating the secondary carrier according tothe indication message received from the base station.

Preferably, the method of transmitting and receiving data using amulti-carrier according to an embodiment of the present invention mayfurther include transferring a deactivation confirmation message of thesecondary carrier to the base station through the primary carrier.

Preferably, the indication message may include carrier index informationindicating an index of the secondary carrier to be activated by theterminal; and operation information indicating the activation ordeactivation operation of the secondary carrier indicated by the carrierindex.

Preferably, the indication message may further include offsetinformation indicating a timing for implementing the operation.

Preferably, it is characterized in that the indication message may haveany one form of an extended subheader, a signaling header, a piggy backmessage, a map information message, and a MAC (medium access control)management message.

Preferably, the method of transmitting and receiving data using amulti-carrier according to an embodiment of the present invention ischaracterized in that the activation of the secondary carrier may bedetermined according to a data traffic status, a maximum sustainedtraffic rate, or a maximum traffic burst size.

In order to accomplish the foregoing object, according to an apparatusof transmitting and receiving data using a multi-carrier in accordancewith an embodiment of the present invention,

in an apparatus of transmitting and receiving data using a multi-carrierincluding a primary carrier for transmitting and receiving variouscontrol information and data for communicating with a base station andat least one or more secondary carriers using the primary carrier andother RFs (radio frequencies), the apparatus may include a firstreceiving unit configured to transmit and/or receive data to and/or fromthe base station through the primary carrier; a second receiving unitconfigured to transmit and/or receive data to and/or from the basestation through the secondary carrier; and a controller configured tocontrol the power of the first receiving unit and the second receivingunit, wherein the controller receives an indication message (Indication)indicating the activation or deactivation of the secondary carrier fromthe base station through the first receiving unit and controls the powerof the second receiving unit to perform the activation or deactivationof the secondary carrier according to the indication message receivedfrom the base station.

Preferably, in the apparatus of transmitting and receiving data using amulti-carrier, the indication message may include carrier indexinformation indicating an index of the secondary carrier; and operationinformation indicating the activation or deactivation operation of thesecondary carrier indicated by the carrier index.

Preferably, the indication message may further include offsetinformation indicating a timing for implementing the operation.

Preferably, in the apparatus of transmitting and receiving data using amulti-carrier, it is characterized in that the indication message mayhave any one form of an extended subheader, a signaling header, a piggyback message, a map information message, and a MAC (medium accesscontrol) management message.

Preferably, in the apparatus of transmitting and receiving data using amulti-carrier, it is characterized in that the activation ordeactivation of the secondary carrier may be determined according to adata traffic status, a maximum sustained traffic rate, or a maximumtraffic burst size.

Preferably, in the apparatus of transmitting and receiving data using amulti-carrier, it is characterized in that the controller may receive anindication message indicating the activation or deactivation of thesecondary carrier to perform the activation or deactivation of thesecondary carrier and transmit a confirmation message to this to thebase station through the primary carrier.

An aspect of the present disclosure is to provide an apparatus andmethod for preventing resource consumption and unnecessary powerconsumption of a terminal by suitably activating or deactivatingmulti-carriers allocated to the terminal according to its capabilitysuch as a data traffic status, a maximum sustained traffic rate, or amaximum traffic burst size, in order to solve a problem of generatingresource consumption and unnecessary power consumption of a terminal ina conventional communication system having a multi-carrier method inwhich CQI channels are allocated or terminal RFs are unnecessarilyturned on though data traffic is not actually generated for all carriersallocated to the terminal.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a view illustrating a multi-carrier system according to anembodiment of the present invention;

FIG. 2 is a view illustrating the management mode of a terminalsupporting a multi-carrier according to the operating state of a primarycarrier and a secondary carrier;

FIG. 3 is a state transition diagram illustrating the mode transition ofa terminal according to data traffic;

FIG. 4 is a flow chart illustrating the process of activating anddeactivating a multi-carrier on the basis of data traffic according toan embodiment of the present invention;

FIG. 5 is a view illustrating that a secondary carrier is activatedaccording to an embodiment of the present invention;

FIG. 6 is a view illustrating that the relevant indication message isreceived when data traffic is terminated according to an embodiment ofthe present invention;

FIG. 7 is a view illustrating that an indication message is receivedthough the tailor information of data traffic according to an embodimentof the present invention;

FIG. 8 is a view illustrating the structure of a traffic indicatorincluded in a signaling header; and

FIG. 9 is a view schematically illustrating the configuration of aterminal supporting a multi-carrier according to an embodiment of thepresent invention.

MODES FOR CARRYING OUT THE PREFERRED EMBODIMENTS

Hereinafter, preferred embodiments of the present invention will bedescribed in detail with reference to the accompanying drawings, and thesame or similar elements are designated with the same numeral referencesregardless of the numerals in the drawings and their redundantdescription will be omitted. In describing the present invention,moreover, the detailed description will be omitted when a specificdescription for publicly known technologies to which the inventionpertains is judged to obscure the gist of the present invention. Also,it should be noted that the accompanying drawings are merely illustratedto easily explain the spirit of the invention, and therefore, theyshould not be construed to limit the spirit of the invention by theaccompanying drawings.

Hereinafter, the term “terminal” is used, but the terminal may be alsoreferred to as a subscriber station (SS), user equipment (UE), mobileequipment (ME), and a mobile station (MS). Furthermore, the terminal maybe portable equipment having a communication function such as portablephone, PDA, smart phone, notebook, etc., or non-potable equipment suchas PC, vehicle mounted device, etc.

I. Multi-Carrier Terminology

FIG. 1 is a view schematically illustrating a multi-carrier systemaccording to an embodiment of the present invention.

As illustrated in FIG. 1, in a multi-carrier mode according to thepresent invention, the number of carriers allocated to terminals 103,105 by a base station 101 to be used for data transmission andreception, or the like, may be at least two or more. According to anembodiment, for the sake of convenience of explanation, it will bedescribed below a case where four carriers RF1, RF2, RF3 and RF4 areused. The base station 101 may allocate multiple carriers RF1, RF2, andRF3 for a terminal 103 to be used in a multi-carrier mode, and a carrierRF4 may be also allocated to another terminal 105 from the base station101. In this case, the terminal 103 operates in a multi-mode by usingone or more carriers, and the terminal 105 operates in a single-mode byusing only one carrier.

In the base station 101, multi-carrier types can be divided into twokinds of groups, a fully configured carrier (hereinafter, “FCC”), and apartially configured carrier (hereinafter, “PCC”). The FCC is defined asa carrier capable of transmitting and receiving uplink/downlink data andPHY/MAC control information, and the PCC as a carrier capable oftransmitting only downlink data to a terminal. Accordingly, the PCC maybe applicable to a carrier mainly used in a Multimedia BroadcastMulticast Service (MBMS), and the like. Referring to FIG. 1, RF1 andRF2, among the carriers allocated to the terminal 103, correspond to theFCC capable of transmitting and receiving uplink/downlink data andcapable of transmitting and receiving PHY/MAC control information of theterminal. RF3, allocated to the terminal 103, corresponds to the PCCcapable of transmitting downlink data only from a base station to aterminal. The carrier RF4, allocated to the terminal 105, corresponds tothe FCC capable of transmitting and receiving uplink/downlink data andcapable of transmitting and receiving PHY/MAC control information of theterminal, and in case of a single-mode type such as the terminal 105,the carrier RF4 is preferably allocated in a FCC type since only onecarrier RF4 is allocated.

From the standpoint of the terminals 103, 105, the types of carrierallocated from a base station can be divided into two kinds of groups, aprimary carrier and a secondary carrier. Preferably, one primary carrierand a plurality of secondary carriers can be allocated to a terminalfrom a base station. According to the present invention, the primarycarrier can transmit and receive data traffic and PHY/MAC controlinformation between the terminal and the base station, and functions asa carrier mainly used for a control function of the terminal such asnetwork entry of the terminal. Furthermore, the secondary carrier can beallocated to a terminal based upon a resource allocation command of thebase station, and is used as a carrier for mainly transmitting andreceiving data traffic. However, the secondary carrier may be also usedas a channel for transferring specific control information between thebase station and the terminal to perform a multi-carrier operation.

Referring to FIG. 1, among the carriers allocated to the terminal 103,RF1 or RF2 may become a primary carrier, and RF3 becomes a secondarycarrier. Similarly, RF4 allocated to the terminal 105 functions as aprimary carrier. As illustrated in FIG. 1, in a multi-carrier system, itis possible at the same time to support the terminal 103 supporting amulti-carrier approach and the terminal 105 supporting a single-carrierapproach only, and the terminal 103 supporting a multi-carrier approachcan be also used as a single-mode using a single-carrier approach basedupon data traffic. However, even if it is used as a multi-mode orsingle-mode, at least one carrier should be allocated, and at this time,the relevant carrier functions as a primary carrier when only onecarrier is allocated.

The primary carrier of a terminal is a FCC-type defined by a basestation, and the carrier that has performed an initial network entryprocedure will be determined as a primary carrier. The secondary carriercan be set to a FCC- or PCC-type, and allocated additionally based upona request or instruction of the terminal or base station. Preferably,the terminal can transmit and receive all control information andsecondary carrier information through a primary carrier, and mainlyreceive downlink data through a secondary carrier. Furthermore, aFCC-type secondary carrier established for a terminal may be establishedas a primary carrier for another terminal.

II. State Transition of Terminal According to Multi-Carrier OperatingState

FIG. 2 is a view illustrating the management mode of a terminalsupporting a multi-carrier according to the operating state of a primarycarrier and a secondary carrier. In the terminal, as illustrated in FIG.2, the management mode types may be divided into an active(multi-carrier, single-carrier) mode and a deactive mode according tothe operating state of a primary carrier and a secondary carrier.

One primary carrier and one or a plurality of secondary carriers are inan active state when the terminal is managed in an activatedmulti-carrier mode, and all secondary carriers are in a deactive statewhen managed in an activated single-carrier mode. When the terminal ismanaged in a deactive state, all carriers of the terminal aredeactivated and the relevant RFs are turned off.

The terminal supporting a multi-carrier may support three states, such amulti-carrier mode in which two or more carriers are activated, asingle-carrier mode in which only one carrier is activated, and adeactive mode in which all carriers are deactivated as described above,and the terminal supporting only a single-carrier may support only anactivated single-carrier and an idle mode. The terminal is operated in amulti-carrier or single-carrier mode according to the state oftransmitting and/or receiving data to and/or from a base station, andfor this purpose, multi-carrier commands are supported as illustrated inthe following Table 1.

TABLE 1 Multi-carrier command Function Activate Carrier Activate one ora plurality of deactivated carriers Deactivate Carrier Deactivate one ora plurality of activated carriers

When the terminal is operated in a single-carrier mode at the time ofinitially entering a network, and thereafter, additional carriers arerequired, additional single-carriers are secured through “ActivateCarrier” in the multi-carrier command as illustrated in Table 1. On thecontrary, when the data transmission and reception of a specific carrieris finished or the connection to the network is terminated, the carrieris deactivated through a “Deactivate Carrier” command. An overall statetransition for the mode transition of the terminal according to suchdata traffic is illustrated in FIG. 3.

Referring to FIG. 3, when a currently activated carrier in the terminalis deactivated, the relevant carrier will be in a deactivated state. Ifall single-carriers are deactivated in such a manner, then the terminalwill be operated only with a primary carrier at the end. When data istransmitted and received only with a primary carrier in this manner, theterminal will be operated in a single-carrier mode 303.

The activation of deactivation of a carrier allocated to the terminalaccording to the generation of data traffic will be described withreference to FIG. 1. In case of the first terminal 103 illustrated inFIG. 1, active carriers in which traffic is actually generated among thecarriers RF1, RF2, and RF3 allocated by the base station may be onecarrier RF1, or two carriers RF1 and RF2. On the contrary, if thecarrier RF3 is included in three carriers allocated to the terminal 103from the base station 101, but classified as an activated carrier evenwhen there does not exist downlink data traffic from the base station,it is preferable to perform a deactivation process for the carrier inwhich traffic is not generated because the relevant RF of the terminalcontinues to be turned on and thus unnecessary power consumption may begenerated. The activation and deactivation of a carrier will bedescribed in more detail in the related section thereof.

The function of activating or deactivating a carrier may be configuredbased on data traffic as described above, but according tocircumstances, may be configured based on the QoS (quality of service)requirements of the terminal, or may be configured based on themanagement object of the base station. For the QoS requirements of theterminal, according to an embodiment of the present disclosure, thecapability for various services currently existing in the terminal mayinclude a maximum sustained traffic rate, a maximum traffic burst size,or the like. Accordingly, the base station checks the service capabilityof the terminal and then allocates the number of carriers suitable tothat. The method of activating and deactivating a carrier according tothe service capability of the terminal is similar to the activation anddeactivation of a carrier based on traffic as described above, andtherefore, the detailed description thereof will be omitted.

Hereinafter, the operation of activating and deactivating a carrierbased on data traffic will be described in more detail with respect tothe related drawings.

III. Method of Indicating Carrier Activation and Deactivation Accordingto Whether there Exists Data Traffic in a Multi-Carrier System

FIG. 4 is a flow chart illustrating the process of activating anddeactivating a multi-carrier on the basis of data traffic according toan embodiment of the present invention.

The terminal performs an initial network entry procedure (S401), andcarrier F1 is used as a primary carrier of the terminal when the usedcarrier at this time is referred to as F1 as described above. Asillustrated in FIG. 4, when the terminal is allocated with F1 and F2 asusable multi-carriers, carrier F1 used in the initial network entryprocedure may be defined a FCC (fully configured carrier) type primarycarrier, and carrier F2 may be defined as a PCC-type secondary carrier.The base station activates or deactivates the relevant carrier if datatraffic to be transmitted to a specific secondary carrier F2 isgenerated or data traffic being transmitted is finished, and for thispurpose, transmits an indication message (Traffic IND) for theactivation and deactivation of a carrier to the terminal.

As illustrated in FIG. 4, if data traffic to be transmitted to thesecondary carrier F2 is generated in a state that the primary carrier F1of the terminal is only activated, then the base station transmits anindication message (Traffic IND) for the traffic generation of thesecondary carrier F2 to the terminal through the primary carrier F1(S411). The traffic generation indication message (Traffic IND) mayinclude information on a traffic generation timing, and additionally,may include index information of an activation object carrier, a commandfor the activation or deactivation of an object carrier, offsetinformation related a time for executing the relevant operation, and thelike. The traffic generation indication message (Traffic IND) may betransferred in any one of Extended Subheader, Signaling Header, Tailor,Piggy back, MAP information, and MAC management messages. The moredetailed description of the traffic generation indication message(Traffic IND) will be described later, and hereinafter, an overalloperation will be described based on the type of MAC managementmessages.

The terminal receives a traffic generation indication message (TrafficIND) of a secondary carrier F2 from the base station through a currentlyactivated primary carrier F1, and turns on the relevant RF to activate acurrently deactivated single-carrier F2 (S413). In this manner, if thebeginning of data traffic transmitted and received between the basestation and the terminal is notified from the base station to theterminal, then the terminal can set up the RF of the relevant carrieraccording to a timing at which data traffic should be received ortransmitted through the secondary carrier. According to anotherembodiment of the present disclosure, the terminal may select a carrierRF suitable to the current QoS service capability to activate, and itmay be notified to the base station through the primary carrier.

Even when the terminal receives a traffic generation indication message,a delay time consumed for the processing of turning on the relevant RFmodule may be generated, and according to circumstances, the terminalmay not normally receive a message transmitted from the base station orthe relevant carrier may not be normally turned on even when received.In consideration of such circumstances, preferably, if the RF modulecorresponding to the secondary carrier F2 of the terminal is normallyturned on, then a confirmation message (Confirmation) to this istransmitted to the base station (S415). The turn-on confirmation messageof the secondary carrier F2 may be transferred through the primarycarrier F1 of the terminal, and according to another embodiment of thepresent disclosure, it may be also directly transferred to the basestation through an activated secondary carrier F2. If an activateconfirmation message of the secondary carrier F2 is received from theterminal, then the base station transmits the generated data traffic tothe terminal through the secondary carrier F2 (S417).

When there is no data traffic anymore generated after performing datatransmission and reception between the terminal and the base stationthrough the secondary carrier F2, the base station transmits a traffictermination indication message (Traffic Indicator) (S419) to preventunnecessary power consumption.

The terminal turns off the RF of the relevant carrier upon receiving atraffic termination indication message (Traffic Indicator) from the basestation (S421), and transfers a confirmation message to this to the basestation (S423).

FIG. 5 is a view illustrating that a secondary carrier is activatedaccording to a traffic indication message (Traffic Indicator) receivedthrough a primary carrier.

The terminal receives the activation information of a secondary carrier(carrier configuration indicator) through a primary carrier, and turnson the relevant RF according to the expected data traffic generationtiming of a currently deactivated secondary carrier and activates thesecondary carrier. When the activated secondary carrier is a FCC (fullyconfigured carrier), resource allocation for persistent trafficgenerated subsequent to being activated may be directly allocated to thesecondary carrier through DL/UP MAP information or the like or allocatedthrough a primary carrier. An ACK message may be transferred to confirmif the activation of the relevant carrier is normally carried out, andthe setting for activating the secondary carrier again may be repeatedif the ACK message is not normally transmitted. When traffic is notifiedthrough the MAP of a downlink-scheduling channel (DL Scheduling Channel)of a primary carrier, traffic scheduling for the next frame is notified.The activation indication information of a secondary carrier may includerelative offset information, and through this, it may be possible tocheck a more accurate timing for activating the relevant carrier. Atthis time, the offset value may be a fixed or previously set value, andpreferably, it may be adaptively configured according to thecircumstance. The unit of a relative offset value may be a subframe orframe unit.

FIG. 6 is a view illustrating that an indication message indicating atiming of deactivating the relevant carrier is received through aprimary or secondary carrier when data traffic is terminated. If anindication message (Carrier configuration Indicator) for thedeactivation of a secondary carrier is received from the base stationthrough a primary carrier or secondary carrier, then the terminaldeactivates the secondary carrier and turns off the RF after currenttraffic is terminated. When the deactivation of a secondary carrier isnormally carried out, ACK for confirming this is transmitted to the basestation through a secondary or primary carrier, and subsequently theterminal turns off the relevant secondary carrier until receiving acommand for activating the relevant secondary carrier again, therebypreventing unnecessary power consumption.

FIG. 7 is a view illustrating an embodiment in which an indicationmessage (Carrier configuration Indicator) for the deactivation of asecondary carrier is received though the tailor information of datatraffic.

In case of FIG. 6, an indication message (Carrier configurationIndicator) for the deactivation of a secondary carrier is receivedthrough a MAC message, but the deactivation timing of a current carrieris notified by adding tailor information similar to a header to the endof data received through a secondary carrier as illustrated in FIG. 7.Accordingly, it has an advantage that the terminal may perform carrierdeactivation at a relatively accurate time and turn off the relevant RFwithout receiving an additional Indicator message.

Hereinafter, a traffic indication message (Traffic IND) will bedescribed in detail.

IV. Embodiment of Traffic Indicator

An indication message indicating the activation and deactivation of amulti-carrier may be configured in any one form of Extended Subheader,Signaling Header, Tailored traffic Indicator, Piggy back trafficIndicator, MAP information message, and MAC management message.Hereinafter, each indication message will be described in detail.

(1) Multi Carrier Extended Subheader Traffic Indicator

Table 2 illustrates an extended subheader type traffic indicationmessage according to an embodiment of the present disclosure.

TABLE 2 Syntax Size(bit) Notes Extended HeaderHeader( ){ LAST 4 LastExtended Header indication: 0 = one or more extended header follows thecurrent extended header unless specified otherwise: 1 = this extendedheader is the last extended header unless specified otherwise Type TBDType of extended header Body Contents Variable Type dependent content }

According to this embodiment, while a terminal supporting amulti-carrier operates with a multi-carrier or single-carrier subsequentto terminating negotiation with a base station, the execution ofadditional functions such as requesting additional allocation of asecondary carrier, deactivating a currently activated secondary carrier,or the like is configured through Multi-Carrier control ExtendedSubheader. The Multi-Carrier control extended subheader functions as anIndicator message, and may include Carrier Index indicating an index ofthe relevant carrier, Operation indicating whether to activate ordeactivate a carrier corresponding to the carrier index, Relative Offsetinformation indicating a timing for implementing the Operation, and thelike.

The kinds of extended subheaders currently being defined may include afragmentation and packing extended header, a fragmentation extendedheader, a multiplexing extended header, and the like. The format of MCEH(Multi-carrier Extended Header), which is an extended subheader formulti-carrier operation, is illustrated in the following Table 3.

TABLE 3 Syntax Size(bit) Notes MCEH( ) { — — Carrier index 8 Indexnumber of the carrier that is to be configured Carrier Action 1 Theindicator whether to activate or Deactivate the carrier. 0: Deactivatecarrier 1: Activate carrier Traffic indicatior 7 The time offset innumber of frames or subframes indicating the time when to take action ofthe specified carrier. Reserved }

(2) Signaling Header Type Traffic Indicator

According to another embodiment of the present disclosure, trafficindicator may be included in a signaling header to be transmitted in asignaling header format. Table 4 illustrates a signaling header formataccording to an embodiment of the present disclosure.

TABLE 4 Type field (3 bits) Signaling Header Type 000 BR with STID 001BR without STID 010 BR with UL Tx Power Report 011 Feedback Header (IM)100 Event Driven Indicator (EDI) Header with STID 101 Event DrivenIndicator (EDI) Header without STID 110 Activation/deactivationindicator for Multi-carrier support 111 Reserved

The field “110” of the signaling header type as illustrated in FIG. 4relates to the activation and deactivation of a multi-carrier, and mayinclude “Carrier Index” information indicating an index of the relevantcarrier, “Operation” indicating information whether to activate ordeactivate a carrier corresponding to the index, “Relative Offset (Starttime)” information indicating a timing for implementing the “Operation”,and the like.

FIG. 8 is a view illustrating the structure of a traffic indicatorincluded in a signaling header. In FIG. 8, Carrier Index 801 indicatesan index for a carrier to be activated or deactivated, which may beconfigured with 8 bits. Action 803 is bit information for activating ordeactivating the relevant carrier, which is configured with 1 bit. Forexample, if the Action bit value is “0”, then it means that the relevantcarrier is deactivated, and if the Action bit value is “1”, then itmeans that the relevant carrier is activated, Traffic Indicator relativeoffset 805 indicates information for a timing of implementing the Action803, which may be configured with 4 bits.

(3) Data Tailor Type Traffic Indicator

As previously illustrated in FIG. 7, a tailor header is added to an endportion of packet data similar to the form of a subheader to inform anend of the traffic of a current packet. In case of this embodiment, anend timing of the traffic may be seen without an additional indicator,thereby enhancing efficiency in the aspect of resource use at the timeof transmitting data. The Tailor Traffic Indicator may include “CarrierIndex” information indicating an activation and deactivation objectcarrier index, “Operation” indicating information whether to activate ordeactivate a carrier corresponding to the index, “Relative Offset (Starttime)” information indicating a timing for implementing the “Operation”,and the like.

(4) Piggy Back Type Traffic Indicator

According to another embodiment of the present invention, informationfor existence or non-existence of traffic and state transition of acarrier may be notified through a piggy back field without an additionalindication message. The piggy backed traffic indicator may include“Carrier Index” information indicating an activation and deactivationobject carrier index, “Operation” indicating information whether toactivate or deactivate a carrier corresponding to the index, “RelativeOffset (Start time)” information indicating a timing for implementingthe “Operation”, and the like.

(5) Traffic Indicator Through MAP Information

According to another embodiment of the present invention, theinformation of a traffic indicator may be notified through MAP.Resources for an indicator is allocated to MAP, and the terminalrecognizes the indication of traffic with reference to the indicatorinformation location of MAP. The traffic indicator MAP may include“Carrier Index” information indicating an activation and deactivationobject carrier index, “Operation” indicating information whether toactivate or deactivate a carrier corresponding to the index, “RelativeOffset (Start time)” information indicating a timing for implementingthe “Operation”, and the like.

(6) Traffic Indicator Through MAC Management Message

According to another embodiment of the present invention, TrafficIndicator is transmitted through a MAC management message defined byIEEE 802.16e. The base station may inform the terminal of a start timingtraffic and an end timing of traffic through a multi-carrier request MACmanagement message. The MAC management message may include “CarrierIndex” information indicating an activation and deactivation objectcarrier index, “Operation” indicating information whether to activate ordeactivate a carrier corresponding to the index, “Relative Offset (Starttime)” information indicating a timing for implementing the “Operation”,and the like. Table 5 illustrates an embodiment of the MAC managementmessage.

TABLE 5 Syntax Size (bit) Notes MC_Management_Message_format_( ) { —Management Message Type = x 8 Carrier Management type 2 0b00: secondarycarrier management 0b01: primary carrier change 0b10: carrier switching0b11: reserved If (message type == 00){ Number of carrier [3] The numberof activated or deactivated carrier(s) Segment type (or CombinedFeedback 1 0b0: MAC segmented carrier (or separated indication)Feedback) 0b1: PHY segmented carrier (or combined Feedback) for (i=0;i++; i< Number of carrier) { If (Segment type ==1){ [3] Carrier Index ofactivated or deactivated Carrier index} carrier(s) If (Segment type==0){Feedback Channel Allocation IE( )} Carrier Action Indicator(Indicator type) 1 0: Carrier activation 1: Carrier deactivation(Deactivate) Start Time 8 The time offset to trigger the Carrier Action(activate/Deactivate) in subframe or frame unit } } If (message type ==01 or 10) { ... If (message type == 10) { ...} } Padding variablePadding bits to ensure byte aligned. Shall be set to zero TLV encodedinformation variable TLV-specific }

Referring to FIG. 5, when the carrier management type has a value of“0b00”, it indicates a secondary carrier management operation and thedetailed description thereof is similar to the foregoing description.

V. Structure and Function of Terminal Supporting a Multi-Carrier

FIG. 9 is a view schematically illustrating the configuration of aterminal supporting a multi-carrier according to an embodiment of thepresent invention. A terminal supporting a multi-carrier according tothe present disclosure may include at least one or more RF receivingunits 903, 905, 909 and an antenna 911. Hereinafter, the description forthe configuration of a typical terminal will be omitted, and only theconfiguration and function associated with data transmission andreception using a multi-carrier according to the present disclosure willbe described. In the terminal supporting a multi-carrier as illustratedin FIG. 9, the RF receiving units 903, 905, 909 as many as the number ofsupportable multi-carriers are independently configured, and each RFreceiving unit transmits and/or receives data to and/or from the basestation through the relevant carrier. Referring to FIG. 9, the RFreceiving unit is configured with a first RF receiving unit 903 fortransmitting and/or receiving data to and/or from through a firstcarrier, a second RF receiving unit 905 for transmitting and/orreceiving data to and/or from through a second carrier, and with an N-thRF receiving unit 903 for transmitting and/or receiving data to and/orfrom through an N-th carrier, and the controller 901 controls the powerof the first RF receiving unit 903, second RF receiving unit 905, N-thRF receiving unit 909 according to whether data traffic is generated ateach receiving unit to prevent unnecessary power consumption from beinggenerated. Preferably, the controller 901 receives an indication message(Traffic Indication) indicating the generation and termination of datatraffic received through the second RF receiving unit 905 from the basestation through the first RF receiving unit 903, and controls the powerof the second RF receiving unit 905 according to the indication messagereceived from the base station to perform the activation anddeactivation operation of a second carrier.

As described above, the first carrier is a primary carrier of theterminal, and the second carrier performs the role of a secondarycarrier of the terminal.

The indication message may include Carrier Index information indicatingan activation and deactivation object carrier index, Operationindicating information whether to activate or deactivate a carriercorresponding to the carrier index, Relative Offset informationindicating a timing for implementing the operation, and the like.

Furthermore, an indication message indicating the activation anddeactivation of a multi-carrier may include Extended Subheader,Signaling Header, Tailored traffic Indicator, Piggy back trafficIndicator, MAP information or MAC (Medium Access Control) managementmessage, and the like.

The activation or deactivation of a secondary carrier may be determinedby the QoS (Quality of Service) requirements such as a data trafficstatus, a maximum sustained traffic rate, a maximum traffic burst size,or the like or may be determined by load condition of carriers or otherfactors.

According to another embodiment of the present invention, the controller901 may receive an indication message indicating the activation ordeactivation of a secondary carrier from the base station to control thepower of the second RF receiving unit 905, thereby performing theactivation or deactivation of a secondary carrier, and may transmit aconfirmation message to this to the base station through a primarycarrier.

The method according to the present invention as described above may beimplemented by software, hardware, or a combination of both. Forexample, the method according to the present invention may be stored ina storage medium (for example, an internal memory of the terminal, flashmemory, hard disk, and so on), and may be implemented by codes orinstructions within a software program that can be performed by aprocessor (for example, a microprocessor within the terminal).

Though preferred embodiments of present invention are exemplarilydescribed as disclosed above, the scope of the invention is not limitedto those specific embodiments, and thus various modifications,variations, and improvements can be made in the present inventionwithout departing from the spirit of the invention, and within the scopeof the appended claims.

What is claimed:
 1. A method of operating carriers at a user equipmentin a wireless communication system, the method comprising: configuring aprimary carrier and a plurality of secondary carriers, wherein theprimary carrier is configured as a carrier for performing a networkentry procedure; receiving a message through the primary carrier, themessage including: an indicator indicating activation of a secondarycarrier of the plurality of secondary carriers; and an index of thesecondary carrier to be activated; receiving a secondary carrierdeactivation time offset, the secondary carrier time offset being anumber of frames; activating the secondary carrier no earlier than aspecific subframe offset, the specific subframe offset being a number ofsubframes after receiving the indicator; receiving data on the activatedsecondary carrier; and deactivating the activated secondary carrierbased on the the secondary carrier deactivation time offset.
 2. Themethod of claim 1, wherein the message is received as a type of a MediumAccess Control (MAC) message.
 3. The method of claim 1, wherein theprimary carrier is always activated and the secondary carrier isinitially deactivated.
 4. The method of claim 1, wherein the secondarycarrier is activated based on a quality of service (QoS) capability. 5.A user equipment of operating carriers in a wireless communicationsystem, the user equipment comprising: a wireless communication unit;and a controller operatively connected to the wireless communicationunit and configured to configure a primary carrier and a plurality ofsecondary carriers, wherein the primary carrier is configured as acarrier for performing a network entry procedure; receive a messagethrough the primary carrier, the message including: an indicatorindicating activation of a secondary carrier of the plurality ofsecondary carriers; and an index of the secondary carrier to beactivated; and receive a secondary carrier deactivation time offset, thesecondary carrier deactivation time offset being a number of frames;activate the secondary carrier no earlier than a specific subframeoffset, the specific subframe offset being a number of subframes afterreceiving the indicator, receive data on the activated secondarycarrier; and deactivate the activated secondary carrier based on thesecondary carrier deactivation time offset.
 6. The user equipment ofclaim 5, wherein the message is received as a type of a Medium AccessControl (MAC) message.
 7. The user equipment of claim 5, wherein thecontroller is further configured that activate always the primarycarrier and initially deactivate the secondary carrier.